52 MORPHOLOGY 



The lateral divergence is often expressed by an angle, 

 and then it is known as angular divergence. Thus 

 the lateral divergence | corresponds to angular diver- 

 gence of 5- of 360° = 180°; the lateral divergence 

 I corresponds to angular \iivergence of ^ of 360° = 

 120°; the lateral divergence f corresponds to angular 

 divergence of f of 360° = 144°; and so on. When 

 the spirally arranged leaves are very close set, in 



v\\xS \X// 



I^iff- 53- — Phyllotaxis of Leaves (transverse) 



Other words, when the divergences are very small, 

 it is often very difficult to make out the orthostichies. 

 In such caseis, however, we find well-marked lateral 

 or diagonal stichies known as para-stichies. These 

 para-stichies can easily be made out on the stems of 

 Date-palms (fig. 51), tal-palms, &c., because in them 

 the leaf-bases or leaf-cicatrices are left behind when 

 the leaves fall off. The above diagrams are given 

 to illustrate the longitudinal (fig. 52) and transverse 

 projections (fig. 53) of \, f, and f phyllotaxy. 



